1. Field of the Invention
This invention relates to a method for manufacturing a dynamic random access memory, specifically, to a semiconductor device having stacked memory cells.
2. Description of the Related Art
In dynamic random access memories employing stacked capacitor cells, various kinds of memory cell structure have been suggested to increase the capacitance value of the storage electrodes. One example is the box-structured memory cell disclosed in "A New Stacked Capacitor Cell with a Storage Node Having a Thin Box Structure", by S. Inoue et al., Toshiba Co., 21st SSDM (Solid State Devices and Materials), 1989, p141-144. This memory cell can provide a large capacitance per narrow area. This type memory cells require the step of forming a cavity inside the storage node or electrode of the capacitance cell. However, it has been very difficult to obtain well-patterned cavity using ordinary photolithography. This is because there is a large level difference between the storage node and the substrate, whereby it is difficult to perform uniform resist coating.